From AT 501 000 A1, a method and an arrangement for dividing glass, in particular flat glass, using laser radiation are known. With this known method, a bundled laser beam is directed onto the flat glass that is to be divided and reflected on a reflective surface arranged below the flat glass. The reflected laser beams are reflected again on the flat glass in the form of two bundles of laser beams, using a reflector that is arranged on the head of the laser and that has an opening for the bundled laser beams, in which reflector two cavity-like, elongated reflecting surfaces are provided. By the bundled laser beam, a microcrack is produced in the flat glass without heating the flat glass. The laser beam bundle reflected by the reflective surfaces on the reflector creates areas heated on both sides of the microcrack. Under the action of the thermal stresses resulting therefrom, the microcrack is opened up over the entire thickness of the flat glass, and the flat glass is divided.
Another method for dividing flat glass with use of laser beams is known from EA 004167 B1. In this known method, a laser beam is used, in particular a CO2 laser, whereby first a focused laser beam is used, and then an unfocused laser beam is used. Using the focused laser beam, a temperature that exceeds the softening temperature is produced in the separating line that is provided. The unfocused laser beam acting on the glass at a temperature above the softening temperature produces additional tensile stresses, so that the separating line that is provided is opened up.
A method for separating glass materials by means of a laser has become known from a publication of the Laser Center, Hannover, EV (http//www.lzh.de). This known method is based on the multiple reflections of an Nd:YAG laser that for the most part is transmissive for glass materials (MULTIPLE LASER BEAM ABSORPTION, MLBA). This method uses an Nd:YAG laser whose radiation is transmitted at up to 85% depending on the glass thickness. The total absorption is increased by multiple reflections of the beam by the glass that is to be divided, and a thermal stress is induced over the entire glass thickness. In this case, an arrangement is used that has a laser head, an upper reflector applied on the laser head, and a lower reflector provided below the glass, i.e., on the side of the glass opposite the laser head.
With this method, several glass panels that lie above one another are also to be divided in one working step, just like composite safety glass (VSG).
Up until now, the practical implementation of the known method has been unsuccessful because of its poor performance and an unreliable process of glass fracture.
From EP 2 286 972 A, it is known to produce bevels on the edges of sides of flat glass panels by a laser beam acting on the glass panel after the latter has been scored in advance using a cutting wheel.
Another method and a device for producing a cutting slit in a glass panel using laser radiation is known from WO 2008/080182 A1. In this method for dividing a glass panel with laser radiation, the glass panel is heated locally by the laser radiation with one or more penetrations of a first surface of the glass panel to a second surface of the glass panel that is opposite and at some distance from the latter and is opened up in the glass panel by the thus produced heat stresses of the cutting slit. The laser radiation is introduced into the glass panel essentially without reflection and refraction on the first surface.
In particular in WO 2008/080182 A, the procedure is to be performed so that the laser radiation is run through an optical component, namely a prism, up to a beam exit face of the same and then is introduced essentially without refraction and without reflection into a liquid that is in direct contact with the beam exit face and from this first surface of the glass panel, in direct contact with the liquid, into the glass panel. In this case, the liquid is to have at least approximately the same refraction index as the glass panel. In this case, it is provided that the laser radiation is introduced at an oblique angle of incidence relative to the axis of incidence in an input point of the bundle of rays by the first surface of the glass surface, whereby the angle of incidence of the laser radiation from the first surface is selected so that a total reflection of the laser radiation is carried out by the second surface of the glass panel.
In the dividing of glass, “laser scoring” and “laser blasting” are known from A. Ostendorf et al. “Licht statt Schneidradchen—Trennen von Glaswerkstoffen mittels Laserstrahlung [Light Instead of Cutting Wheels—Separating Glass Materials by Means of Laser Radiation],” in the Future of Glass—from the Tradition of High-Tech Products, 5th Symposium; June 17-18, Zwiesel 2004, pp. 31-40. This bibliographic reference also mentions the post-treatment of laser-separated glass materials, in which a glass span is to be blasted on the edge by means of a CO2 laser in order to produce a crack-free bevel. However, the method known from the above-mentioned bibliographic reference without details is to be usable only in the case of laser-separated glass components, since otherwise separated glass parts would be immediately destroyed during heating by means of laser radiation.